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Can heated air be provided in the cabin in commercial airlines?
Having travelled quite a number of times, there are times, when the cabin becomes a bit too cold, or people with certain condition get shivering quickly. In such circumstances and generally, is it possible to request for heated air in the cabin. If not the entire cabin, but atleast to specified seats, via the air flow controller on top of the head.
Before that, are airlines equipped to provide heated air, like in a car?

related: https://aviation.stackexchange.com/q/17641/1467 (see also the linked questions)

Can it be provided? Yes, sure. Is it provided? Not that I'm aware of. Generally, the cabin will heat up pretty quickly with all those self-propelled heaters moving around, and needs to be cooled. There are, of course, those who are always cold (like my mother), and for them, the airlines usually provide blankets.

Oh, and the smart ones (like my mother) wear lots of clothes knowing they'll be cold. Seriously, she wears ski pants to fly in so she'll stay warm. Actually, she wears ski pants nearly all year round so she can stay warm...

Even all those people in the cabin together are not enough to heat it up when the outside temperature is -52°C. So yes, heat is provided, but I do notice in general they keep the temperature at the lower end of being comfortable. Too cold for many

The fresh air vents near your head at each seat can not be adjusted for temperature individually.  Cabin temperature is controlled. Just ask a Flight Attendant to warm it up as they have a control panel to adjust cabin temperature by zone.
Most modern airliners use bleed air from the engines to power two Air Conditioning Packs which circulate cooled or heated air throughout the cabin.
Environmental control system (aircraft)
B777 Air Systems

20C? No wonder it's so cold! (for reference, the temperature recommended by the government here is 25.5C)

25.5C (78F)?  That's napping weather right there! You heat the interior of a plane to 25C, then fill it with passengers, it's going from springtime warm to summer time hot in 30-45 minutes!

Except that if you ask the flight attendant to warm it up, I'll probably ask to have the heat turned down :-)  After all, as noted above, people who are cold can always ask for blankets or wear warmer clothes, while overheated people taking off clothing could be considered socially unacceptable.

@FreeMan I think I'd still prefer 25.5C over 20C (68F,) though, particularly while sitting down inside. I seem to recall reading from Korean Air that they keep their cabins somewhere in the upper 70s during flight, but they operate mostly long-haul flights where people want to sleep anyway, so sleeping conditions aren't a bad thing there.

The UK legal minimum limit for office temperatures is 16C (61F) and the recommended temp is 20C. There is no legal maximum (the recommended maximum is 30C), but if the temp in my office was stuck on 25C I would be complaining that it was too hot. 20C or 21C is about right by UK standards.

So what is the legal minimum and maximum temperatures allowed in an aircraft,  say in US and UK?

I am not aware of any legal minimum. The default position at Auto commands 23 degrees and that is where I generally leave it for both the flight deck and cabin.


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How does this very long tube deployed from the back of a 787 measure pressure?
Photos in the CNET's Up close with the first Boeing 787-9 include the one below with the caption

Boeing 787-9 at Farnborough The back of the first 787-9 has coiled tubing extended from the back of the plane's tail during test flights. It's used to measure the true air pressure to compare with the different higher and lower pressures near the plane.

Apparently this is from 2014.
Question: What is this kind of tube called, how is it used, what structure is at the far end of the tube when deployed, and why does it need to be so long?

Published:July 13, 2014 Caption:Stephen Shankland Photo:Stephen Shankland/CNET

Trailing cone. See What is the purpose of the ball and string attached to the tip of the vertical fin on test aircraft? or this one which was closed, but seems even better: What's the purpose of the cable connected on the top of the fin?

@Gerry sounds good to me, I've voted to close as well.

source: Stack Exchange

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sort: votes


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How are these flywheel-like devices used in the Boeing 737 Max?
The recent news video CNN's exclusive look inside a Boeing 737 Max simulator shows a 737 Max simulator cockpit. There are a pair of what look like large black flywheels on the console, shown spinning on their own, and then coming to rest.
What do these do, how are they used, and why is such a large, apparently very haptic device felt to provide the pilot with the best information and/or interaction?
In the real plane (not this simulator) do these connect by cables directly to moving surfaces, or are they actuated only in order to provide information in the cockpit?

Related, maybe a dupe?

what these do: What are the advantages of a Trimmable Horizontal Stabilizer?

I've closed my question as a duplicate. Normally I'd keep the question here to help point readers to the duplicate answer. But if the drive-by down votes continue I'll delete instead.

I'd leave the question here exactly as a pointer. The more paths we have to get people to a useful answer the better.

I know, I was just encouraging you to leave it here, despite any downvotes :-)

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Could the Mars helicopter Ingenuity have been test-flown outdoors at JPL just for the heck of it? (not that they would)
The Ingenuity helicopter that has flown on Mars is designed for roughly 0.01 bar pressure and a colder atmosphere made of mostly CO2. See links (including video) in this answer to What JPL laboratory is this exactly, and what are the functions of these amazing-looking control panels? in Space SE and sources linked within. For more about Mars' atmosphere see this answer to What could Perseverance listening to Ingenuity reveal? there as well, and sources within.
The counter-propagating rotors (driven by separate motors but synchronized) spin at about 2500 RMP. The propellors are huge by Earth standards compared to the tiny weight that they carry. But we also have to remember that it will weigh more on Earth. See answers to Does Ingenuity rotate via differential rotor speeds or differential angles of attack? and sources within for more on that.
Question: Hypothetically, could the Mars helicopter Ingenuity have been test-flown outdoors at JPL just for the heck of it? Not that they would ever do such a thing (it will have been kept very clean and very very safe at all times) but from a technical stand point would it have flown? What rotor speeds and torques would have been necessary, and would these have been possible with the light-weight motors optimized for Mars flight?

also of interest: Did the FAA license the Ingenuity helicopter to fly on Mars? and also Why is Rocketlab working with a Federal Aviation Administration to investigate an early 2nd stage engine shutdown? (bounty just added) Different but related here in Aviation SE: Can we bring a rotorcraft like Ingenuity to an altitude of the same pressure as the one on Mars?

That last one was from yesterday ..

I don’t think that enough information is public to say for certain, but the aircraft would need to generate more than double (2.64) times the lift that’s required on Mars.  With the air being 100 times more dense than the Martian atmosphere, the rotors would experience their nominal torque at much lower speed and it’s doubtful that the motors would be able to generate the required power so far below their design speed.

@Frog The motors are discussed in this paper found in ymb1's answer but I'm not sure if this is definitive for assumptions about a torque curve. Some kinds of motors have most of their torque all the way down to zero speed but for these I don't know. "...two brushless direct-drive propulsion motors driving the two rotors..."

I haven’t studied the paper, but at 1% speed you’d need 100x torque for the same power

Scaling props and motors for Earth vs Mars, paywalled:  https://arc.aiaa.org/doi/10.2514/1.C032086

No, Ingenuity was too heavy and underpowered to fly while on Earth.
From 27:30 to 29:00 in the video of a 2021 May 13 press event, one of its designers, Matt Keennon, manually pilots what he called a "terrestrial version of Ingenuity,"  officially named Earth Copter, nicknamed Teri or Terry.  (Reporters have had to guess at the spelling.  The transcript of a 60 minutes segment has Terry, but that neglects I for Ingenuity.)
At 24:45 Matt explains that its only significant hardware differences compared to Ingenuity are that it is lighter (he doesn't say how much), and that its motors are taller, with twice the torque.  Aerovironment hasn't published any hard numbers about Terry, or possibly even any text at all since even its name remains disputed.
But it's clear that they designed Terry to closely mimic how Ingenuity would fly on Mars (see the section "Iterations" in Inside Ingenuity With AeroVironment), so they wouldn't have lightened it and used much more powerful motors for capricious reasons.  It had to actually fly.  A direct quote from Matt at 24:45:

We also reduced the weight of Terry compared to Ingenuity because it's flying in Earth's gravity.

Co-designer Ben Pipenberg also says:

Terry is designed to fly here on Earth, so the motors were redesigned and are more powerful and have a higher torque to handle the denser atmosphere and the higher gravity.

This is very helpful, thanks! Since the density is of order 100 x difference and these changes are of order 3-5 we can guess that the scaling will scale as the cube root of density. Hopefully we'll get the math at some point and can then find out. Thanks!

AeroVironment has the math, of course, but asking them to publish prematurely would be as effective as asking SpaceX to!  Matt does respond courteously when asked for very specific things that obviously only he knows, but I'm careful to not overstay my welcome.

...test flown outdoors at JPL just for the heck of it

Perhaps if they wanted to lose their jobs as engineers, but if one were to try it:
Ingenuity is a constant speed/variable pitch rotor design.  Earth gravity is 2.64x greater than Martian.  Rotor speed is 2500 rpm.  Rotor diameter is 4 feet.  Rotor tip velocity is:

2500 rpm × 4 feet × 3.14 × 60 min/hr × 1 mile/5280 feet = 340 mph

Why so slow?
Speed of sound in CO2 is slower (78%) than air.  In helium it travels almost 3x faster! Speed is sound is also slower at colder temperatures.
These factors affect the Martian design.  The rotors will work fine on Earth but ...
On Earth they will have to lift 2.64 times more weight.

Lift = Coefficient × Area × Velocity$^2$ x Density

If air density is 100 times greater rotor pitch control would be much more challenging.  Assuming you don't burn out the motors trying to get 2500 rpm, the helicopter would probably crash from excessive control inputs.
Forging ahead, we could reduce the RPM spec for Earth flight:

Square Root 2.64 x 2500 rpm/100 density factor = 40 rpm!

or employ smaller rotors, making it much more controllable. Adding a bit of buoyancy with a helium dirigible attachment would also be possible.  Then, it may be flyable.
A final consideration would be the effect of Reynolds number on the performance of the rotor blades.  Here the Martian atmosphere and higher blade velocity would offer an advantage.
Reynolds number = chord × Velocity/Kinematic Viscosity
In summary, a re-design would be in order for the Earth Ingenuity, but, conceptually, the contra-rotating, variable pitch, constant speed approach (with or without gasbag) would be of interest.

Nice answer, thanks! It's operated at at least a roughly constant speed and likely optimized for it, but are we sure they can't just instruct a different speed? I don't think we should assume the speed is permanently fixed. Alas I still can't find a description of the exact motor beyond "...two brushless direct-drive propulsion motors driving the two rotors..." but I think we should allow for the probability that the speed can be changed

@uhoh judging from airfoil polar data, those rotors would need to be spun fast enough to get most of them above a Reynolds of 10$^6$, where L/D ratio is much better.  But, from a marketing point of view, how many people will run out and get an Earth modified Ingenuity drone from the hobby store.

Given the higher gravity on Earth, the effective mass of the craft on Earth is higher than on Mars.
The drag is also far higher because of the higher atmospheric density.
Both are factors causing more lift and power to be required, in the form of larger rotors and stronger engines.
Luckily the denser air also means more lift per unit of area of the rotors, reducing the required rotor size, somewhat offsetting the requirement for larger rotors.
I don't have the math or the data to make the required calculations, but it's unlikely that a craft designed to be as small and light weight as possible to work in a Martian environment and be able to be launched on the available cheapest launch vehicle available (cost...) would be well suited for use on earth.
It's possible but unlikely.

I'm not exactly taking an opinion pole here, "it's unlikely" without any support based on anything besides "optimized for A means can't work for B" is a comment, but not really a Stack Exchange answer. Someone could write a similar sounding answer with the exact opposite conclusion and there'd be no way for readers to tell which was right.

The effective mass will be identical on Mars or anywhere.  The weight will be different.


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What does the acronym PDA stand for in the aviation domain
While reading an article about Hang Gliding reserve parachutes, I came across the acronym "PDA".  The article seemed to imply that this is a type of parachute and a further google search seems to confirm that.
What I haven't been able to find is a source explaining what this acronym stands for.  Wikipedia disambiguation offers no help and neither do several aviation glossaries I a familiar with.  Lastly, a search for "PDA" in this forum provides no results.

In the article they mention a "Pulled Down Apex", which is a particular type of parachute.  Perhaps that's what they meant?

Pull-down apex. It's an additional attachment point in the center of the parachute. Putting force on it makes the parachute open up more like a half-donut, rather than a half-sphere. That provides more effective area for an annular parachute. That hole in the middle is needed for stability.

Link: one product of this type with a bit of explanation.


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How can we calculate the benefit gained from taping glider wing roots?
Most (all?) glider pilots will be familiar with the practice of taping wing roots.  As most of the gliders in my glider club (and I would guess, in the world) are stored with the wings detached, the practice of taping wing roots to close the gap between the wing and the fuselage is one which is hard to get through glider training without learning.  Indeed, even the type/brand of tape used can be a subject of hot debate.  This picture shows what a taped wing root looks like:

I've always wondered though how critical this practice is.  The gap in wing roots, once spar pins have been inserted, is typically pretty small.  I've forgotten to tape, but I usually don't forgot, partly because I know someone in the club will point out that I've forgotten and a fresh debate ensues.  I would say I'm currently skeptical (but open minded) about the benefit of doing this.
Question:
How effective is taping wing roots?
Lets take, for example, the Schempp-Hirth Open Cirrus, which has a published maximum glide ratio of 44:1.  Lets assume this glide ratio was calculated with the wing roots taped.  This assumption is bolstered by the fact that the rigging check list (Open Cirrus Flight Manual, Page 20) has taping the wing roots as a step.  What would the glide ratio be reduced to if the wing roots are not taped?  I do understand that the answer would depend on the width of the gap.  Lets assume that is 1/16th inch (1.5 mm) for this example.
Secondary Question:
What would the answer to the same question be applied to the gap tape used between the aileron and the wing, as is shown in this picture:

"Every little bit counts"? +1 though.

Calculating the benefits of reduced cockpit noise is really difficult...

It's not just gliders, air racers do the same thing (scroll down to the photos at the end of the article)

Very good point @Pondlife and I would definitely expect to see this practice followed religiously for glider racing.

I find that the main benefit beyond the noise created by wind blowing across the gap is avoiding having the clean fly corpses out of the gaps. You can clean dead flies from the leading edge with a damp cloth but embedded dead flies need a bit more effort and is a less pleasant task.

Great...got the nice question badge, now can anyone answer it?  Was really hoping one of these young hot shot aeronautical engineering students would scoop this up!

The professional glider racers I know swear it gets them an extra degree or two glideslope - but I have no maths, just anecdote

Extra question: what about cleaning wings to remove insects?

It's the tape that holds the wing. If you don't tape it, it'll fall !

The two questions actually concern very different issues.
The second question is easier to answer. Let's take your thought on:

I've always wondered though how critical this practice is.

It is pretty crucial! If you did not tape the gap between the wing and the aileron, you increase chances of a stall. This is especially true at low speed and large angles of attack, i.e. while thermaling or landing. Then an airflow from the lower side of the wing to the upper side might occur, through the gap, destroying the upper side's airflow. This very certainly leads to a performance penalty but also favors stalls. There have been some prototypes experiencing exactly this loss in performance (I could provide more detailed references if desired). I haven't heard of a stall related to this issue, and it actually might be unlikely to happen because under the described circumstances the transition point from laminar to turbulent flow is rather close to the wing's leading edge anyway. Nonetheless, the possibility of increased stall probability should be considered and, imho, is reason enough to never ever fly without aileron tapes.
The first question can only be answered qualitatively, at least with today's methods. It is effective: the airflow, although transitioned to turbulence by the tape, is definitely less turbulent than without the tape. Any kind of turbulence model will consider the "amount" of perturbation, i.e. larger discontinuities of the surface lead to stronger turbulence, thus more drag. You could fly with only one wing taped and see if you can notice a difference. If you notice rolling or yawing, then that's in favor of the corresponding wing. Honestly speaking, I doubt anything can be noticed if the wing consists of one part only, because the asymmetric drag is so close to the center of gravity (only at wing root). But if the wing is made of multiple parts, that might actually lead to some practical result. I am thinking of, e.g., Schleicher's ASW 28 or ASG 29 that have inner and outer wing parts + winglet, meaning 3 tapes distributed over the half wingspan. However, please check the manual of the glider first, if flying without tapes is permitted by the manufacturer.
And then there is also the noise issue.
Given all this information on the one hand and comparing it to the cost of tape and the time it takes to apply it, there is no reason not to use sealing. (Except, of course, around the canopy. You wouldn't expect what kind of ideas people can come up with)

Did I say anything wrong?

I, as the OP did not think so.  At least my upvote can get you out of the negative.  Why do people down vote without an explanation???

Addendum: If the wing consists of multiple parts, there are multiple gaps that can be taped. E.g. Schleicher single seaters ASW 28, ASG 29 have the inner part of the wing, the outer part, and the wing tip, i.e. 3 tape positions per wing. There it is more likely to actually notice anything when flying with only one side sealed, than it is with single-part wings. Even if there was large drag at the wing root it would not produce any significant moment because it is so close to the center of gravity.

Small suggestion...instead of providing this as an addendum, edit your original post.  This ensures that people reading your answer get the whole story without having to sift through comments.  I believe it also moves the question/answer up in the active queue, making it more likely you will get additional votes.

@bclarkreston Done. Could be shortened, but don't have time for that atm.

At this point, I think this is about the best answer I'm going to get to this. I've brought this up to several of the veterans in my club since I asked it here and gotten similar answers along with the suggestion about trying it on one wing (which I have not yet done).  I will update the question to include the conclusion I have gleaned based in theirs and your comment.  Thanks for taking the time to answer!

Based on what I have heard, the  difference makes up for about 1 or 2 glide points.
I can imagine that this does also play an important role to interference drag between the fuselage and the wings. Interference drag means that the sum of the drag forces of the wing alone and the fuselage alone will mostly be a lot less than the drag of the components when assembled as a whole system. That is because the airflows around the object influence each other.
Interference drag
If the gap is very close to the fuselage like it is on the Astir Cs for example, I can imagine not taping might play an even larger role on interference drag. In that case the gap will be inside the boundary layer of the fuselage and all the accelerated airflow going alongside the fuselage will pass through that critical area on the wingroot. That would make up for a drastical increase in total drag force.
Induced drag
An airflow from the lower to the upper side of the wing would also, besides from promoting a stall, cause an increase in induced drag as the air will try to even out the pressure differential from both sides of the wing by passing through the gap.
Parasite drag
Lastly the parasite drag in general will increase as the flow around a seam parallel to the airflow is especially bad for performance. Along such gap the airflow will be very turbulent as many vortices will form resulting in a higher drag force.
For that reason sailplane manufacturers are trying to avoid gaps parallel to the airstream. This can be seen when comparing the shape of modern plane's canopies to that of older designs.
To the second Question
In this case the gap is perpendicular to the airflow. So actually not as bad as if it would be parallel. In this case however, the tape tries to ensure that the airflow over the wing stays laminar for  as long as possible which can only be obtained by a very smooth surface that the airflow can follow without separating from the wings surface and without forming vortices. Laminar flow causes significantly lower drag than turbulent flow does. Once the flow is turbulent though it will not become laminar again that quickly. So it is important to keep that from happening in the first place.
Interestingly supporting the flow at or shortly after the separation point to form vortices and to become turbulent can actually delay airflow separation and reduce drag. That is why some planes use zigzag shaped transitions to the ailerons acting as vortices generators. In case you ever wondered why there is zigzag tape shortly before the trailing edge of some glider wings and elevators.

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Female aviators
I have a friend who is convinced that there are some jets that can't be flown by woman. The argument was that the pressure created by the speed and altitude could burst the uterus... This sounds a great deal dramatic and when I researched it I couldn't find anything about it. But then again, I couldn't find a lot about female aviatiors as a whole.. But since I keep hearing this, I just can't get it off my mind.. Do anyone have any comments about this? Thanks in advance:))

This is complete nonsense. For what it's worth, we have female fighter pilots. Female pilots in the civil sector is even more common.

Hi.  Welcome to  Aviation.SE.  Sorry, but this one is total nonsense.  Everything from the smallest aircraft to the Space Shuttle is flown by women. Voting to  close.

I'm voting to close this question as off-topic because it is not a question and the proposition it presents is nonsense.

Speed doesn't create force on body, acceleration does, and acceleration in airliners has nothing special as passengers can testify. On the other hand there are famous aerobatics female pilots, and as @Simon mentions famous Shuttle female Commanders too.

I'm voting to close this question as off-topic because it belongs to https://skeptics.stackexchange.com

@PeterKämpf Skeptics only deals with notable claims. "I read in the newspaper that X" is fine, but "My pal told me X" isn't sufficient for a Skeptics question. Also, even if the question was on-topic somewhere else, that wouldn't be a reason to close it here.

This is the sort of nonsense that people said 150 years ago to make women ride side-saddle on horses and keep them off bicycles. It's complete nonsense. None of these things will "burst her uterus" any more than they'll burst her (or a man's) bladder, stomach, intestines or anything else.

I wonder how your "friend" felt about female astronauts.  Maybe a browse through Wendy Lawrence's c.v. would be useful.

@KorvinStarmast Actually, back in the day, NASA actually studied what would happen if a woman had a period in space. Gotta love the 50's

@TomMcW Given that some of the early NASA scientists preferred working with monkeys, I am not surprised by a variety of their proposals and research questions.

It is absolute nonsense. There are female F16 pilots who can pull 9g with all of their body fully intact, while you and I would suffer from a blackout.
To even publicly launch such a statement without any scientific backup is a disgrace.

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Being told to monitor a frequency, when are you allowed to transmit on that frequency?
Changing frequency, how long do you have to wait before you are allowed to transmit if you have been told to monitor the frequency. Is there a specific time limit? In what aviation manual can the answer be found?

I'm often told this "taxi to parking, monitor ground point-9" after landing. It doesn't mean I can't talk to ground, it just means I don't have to, since I already have my clearance. If I need something from ground I can contact them immediately, there is no requirement to wait.

First a note on phraseology. In the context of your question, I believe the FAA uses monitor like most of the world uses stand by. I'll be covering the general procedure - if you are in FAA land, replace stand by in my answer with monitor.
If told to monitor a frequency, you are not expected to transmit on that frequency. Monitor is used when a pilot is requested to listen on a frequency to retrieve information from a broadacst. For example, I might tell you to Monitor ATIS 122.750. I then expect you to tune 122.750, listen to the ATIS transmission, and then return back to my frequency afterwards.
If told to stand by on a frequency, you are expected to tune that frequency and wait for air traffic control to contact you there. For example, Standby for Tower on 118.1. When standing by on a frequency, air traffic control is supposed to contact you, not the other way around. However, if you do not get contacted within a reasonable amount of time, you should go ahead and transmit. There is no fixed rule for how long you have to wait - use common sense - just like you would if told to stand by on your current frequency. For example, if you are waiting in line for departure and there are 3 aircraft ahead of you, don't expect the tower to call you before you are next in line for departure. On the other hand, if you are holding short of the runway and there appears to be no other traffic around preventing you from taking off, if the tower hasn't called you within a minute or so, please do try to call them instead. Maybe the controller is busy dealing with other stuff, or maybe they have simply forgotten about you. It does happen, although not often. You could also accidentally have tuned the wrong frequency, and might only realise this when no one replies to a call made by you. It goes without saying that, if you have a safety related message, you transmit it without delay.

I've never heard a controller in the US say "monitor" when they mean "stand by". I don't believe the US uses it in that context anywhere, it would be confusing.

@ronbeyer What I meant was, US controllers use "Monitor tower 118.1" instead of "Standby for tower on 118.1". I am fully aware that they don't use "Monitor" with the meaning "Wait, I will call you back." Answwer edited to clarify.

I understood the meaning, I've never heard it that way. I've never been told to transfer to a frequency and "wait to be contacted", it is always "contact Tower on 118.1" and I change frequencies and say "XYZ tower, N12345 Inbound to land two-four", tower will then respond or say "12345 stand by"

@ronbeyer It does certainly exist in the US as well. Took me 5 seconds to find this on Google: https://www.faa.gov/documentLibrary/media/Order/ATC.pdf. Searching for "monitor" in that document proves it.

FAA Pilot/Controller Glossary MONITOR− (When used with communication transfer) listen on a specific frequency and stand by for instructions. Under normal circumstances do not establish communications.

"When used with communication transfer" - Key takeaway from that would be when "monitor" is used with a transfer of communications. Telling you to monitor a channel and wait for instructions isn't a positive transfer. I agree with Ron here. I know the term "monitor" does exist in US airman lexicon, but I don't think it means what's implied here. "Monitor" is for actively listening to a frequency. Even the documents posted seem to support that. .....

... It doesn't come across as an instruction to change freq and wait to be contacted. And if a controller issued a "monitor" without a "contact" instruction, I'd be asking for clarification. That's not standard phraseology. Regardless, you shouldn't leave a frequency without a positive transfer. "Monitor" doesn't accomplish that.

I guess I just don't see an instruction to go to a channel and wait for the controller to contact you as being a realistic situation. Even in a busy airport, I will be told to "Contact x", and if they are very busy and can't immediately acknowledge, they should get back to me within 5 minutes. If they don't, I should contact them again. My initial contact lets that controller know I am there and about to be in his/her control space.

And to answer the original question..... JO 7110.65W, which was the ATC doc previously posted, 2-1-17.b."NOTE−
For the purposes of this paragraph, a reasonable amount
of time is considered to be 5 minutes from the time the
aircraft enters the controller’s area of jurisdiction or comes
within range of radio/communications coverage..."

Very good comments, thank you. Shawn, is it possible to post a link to the document in question?

@Shawn I might be misunderstanding your comments, but flying in the US, particularly at busier airports, it is very common for me to be told by ground something like "N123XY, monitor tower, good day." and they certainly do mean to switch to the tower frequency and wait for them to call you, and not the other way around.  It also happens when clearance says to monitor ground for taxi. It helps with frequency congestion since you calling them only to hear "standby" (over and over for each airplane) would add two unnecessary transmissions.

@Lnafziger I haven't been flying for many years, so I don't know if SOPs have changed, but I doubt they would have. I have been told to monitor a frequency, but never with the expectation to change the channel and wait for a call to me. If it was for an active contact or a transfer, I was always instructed to "contact x". Or at least always expected to switch the channel and simply announce my presence. Otherwise, how would the controller know I made it there? If they were busy, they'd get to me when they could.

@Shawn Well, if they told you to "contact x" as you say, then you are expected to contact them.  If told to "monitor x" then you should do just that: switch to the frequency and monitor it.  They have internal procedures so that they know who has been instructed to monitor the frequency, and as a pilot, it will be obvious if you misdial a frequency because you won't hear any transmissions to/from other aircraft.  As I said, it's typically done at very busy airports and they pass the strips between different stations so that they know who is waiting.

@Lnafziger I stand corrected. I spoke with my dad, who has been a FedEx pilot since 78. Airlines operate in a slightly different environment than everyone else, but he did say that he has heard that phraseology, usually on taxi when nearing a runway or takeoff position. He did say that usually, even in busy airports, they still want positive exchange of an aircraft, so a request to monitor doesn't always mean to leave the current channel and wait for the other to contact you. Though if you do hear it, they don't want you talking. ...

... I just found it odd, because I have never heard it that way. Even flying to busy Atlanta and a couple of others. Though I will admit to having limited experiences in some of the larger stops in the US.

FAA  has a specific intent with Monitor.  This is clear when reading FAA ATC Handbook 7110.65, section 2-1-17.      c. In situations where an operational advantage will be gained, and following coordination with the receiving controller, you may instruct aircraft on the ground to monitor the receiving controller's frequency.
EXAMPLE-
"Monitor Tower."
"Monitor Ground."
"Monitor Ground Point Seven."
"Monitor Ground, One Two Zero Point Eight."

To be clear, Cessna N1234, taxi to the ramp, monitor ground point 9, means cleared to the ramp, but listen to ground point 9 for further clearances or for further communication.
You only need to initiate contact, if any is needed.  There is no expectation that you will contact ground (in this example) unless you have a need to.
In contrast, stand by, means wait for further instructions (specifically for ATC to get time to deal with you), and avoid further contact until contacted.
Also, after a clearance, followed by monitor ground point 9, there may never be any further communication.  One just taxi's to the ramp, and when off the controlled portion of the airport, one is free to stop monitoring, and shutdown the radio.

Mongo, If you get told by ground to monitor tower frequency, when are you allowed to tell the tower that you are ready, to ensure a smooth operation? ( You want to take off without stopping)

@WalterEVice, any time you have the need.  Normally one will not be told to monitor the tower after a taxi clearance.  But if that were to happen, you can simply call the tower when you have a request. So to answer simply, you are allowed to call at any time, if there is a need.

Mongo, what is your experience and involvement in aviation? I do agreeing with your answer.

44 years as pilot, 37 as CFI-AI, 29 as FAA lead safety rep, corporate test pilot, research scientist in remote sensing and position and time systems, weapons delivery navigation and guidance systems design, other things like seaplane, gliders, towing, etc for fun. 14k hours PIC.

Thank you Mongo! Do you perhaps have a reference for your answer?Hope to buy you a beer somewhere on our globe!

It may be in the FAA AIM, but I can also tell you that it is general practice. For example, late at night, when traffic is down, many towers go to reduced staff. One person may be monitoring tower, ground and clearance delivery.  When a call comes in, they answer it.  If they handle someone who just landed, they will tell them after clearing the active to taxi to the ramp and monitor ground. They say that because that way you will hear other ground movements. (You may also hear the tower on the tower, ground and sometimes clearance frequencies.)

Mongo, I agree with you, however I have a fellow crew member that disagree and the only way to convince him will be with documented proof. I can't find any written evidence and was hoping that someone might help. It seems that common sense is not all that common!

Here's an article http://atccommunication.com/monitor-the-tower  If you need FAA document, reference ATC handbook 7110.65 section 2-1-17 Radio Communications Transfer:     c. In situations where an operational advantage will be gained, and following coordination with the receiving controller, you may instruct aircraft on the ground to monitor the receiving controller's frequency.
EXAMPLE-
"Monitor Tower."
"Monitor Ground."
"Monitor Ground Point Seven."
"Monitor Ground, One Two Zero Point Eight."


text:
How is Reynolds Number derived and used?
Reynolds number is the ratio between inertial forces and viscous forces according to wikipedia. However, I still do not understand its derivation process and how to, for example, calculate the Reynolds Number for a cylinder in large pond of water with the water moving in a direction with speed v.

Which bit have you got difficulty with?

@Koyovis: My question is mainly about how to apply this concept, so for a cylinder in a fluid, how would you calculate the number?

You'd go to Physics SE and ask them. This is not an aviation question at all - your example is at best, a boat, and certainly not an aircraft.

A way it's applied in aviation is to do accurate scale models -- see for example How are wind tunnels used with scale models?.

I don't like the derivation of $Re$. For most of the non-linear velocity profile $\frac{v}{L} \neq \frac{dv}{dx}$. Are we living in pre-calculus era? This may be used in the 19th century because of the lack of measuring techniques. It is still followed in the 21st century even after having CFD and PIV. Please correct me, if I'm wrong.

You can derive the Reynolds number by non-dimensionalization of the Navier-Stokes momentum equation: Wiki link
The choice of reference length and velocity is somewhat arbitrary: usually they are chosen so that they represent "fundamental" dimensions of the study case, e.g.:

For a cylinder in a flow: freestream velocity and cylinder diameter
For a pipe: mean velocity and inner diameter
For a flat plate: freestream velocity and distance from leading edge

In the end of the day, it is a matter of conventions, but what you choose must be physically relevant (e.g. you cannot choose the plate thickness) in a way that, increasing either of them, you go from laminar to turbulent flow. Once the choice of the above pair (length, velocity) is standardized, you can define a critical Reynolds number, which marks the boundary from laminar to turbulent flow (actually, a range of it because of the complex behaviour of fluids during laminar-turbulent transition).

Experimentally it is found the larger is the ratio of inertial force to viscous force the more turbulent is the flow
The trouble is be able to get from the experimental conditions predictable results applicable to real condition
In the theoretical abstract model a volume is a cubic length, while an area is a square length, thus in the abstract we are not trying to determine to what reel volume this applies neither to what real area this applies, that’s why the volume does not show as L x l x H  and the area does not show as L x l .
In order to go from the abstract to the real condition and since the Reynolds number is experimental and to standardize the matter it has been accepted to consider a characteristic dimension for every shape, such as for open large area, narrow section pipe, square pipes etc
As a conclusion in the derivation the characteristic dimension is given nominally as simple as possible that’s why it looks strange.


text:
Why the moment arms in x-direction are considered as -x?

Thanks for anyone reading this question. I am able to understand the signs of the forces, but I could not understand why a negative sign is added to the moment arm in x-direction (please check the last line in the picture).
Thank you!

In your drawing, force is defined positive when upwards. By convention, pitching moment is defined positive in aircraft nose up direction. Origin of the moment is the wing leading edge, so a positive force yields a nose down moment which is negative.
Horizontal forces result in a nose up moment when above the origin, and nose down when below the origin.
That is assuming:

Positive is up, for force and position.
Positive is aft, for both force and position.
Positive is nose up, for moments.

That is the sign convention for which the equation in the book holds. The book should state the sign convention it is using, perhaps you can post that as well.

How about in y direction, how could the force in y direction create any moment?

Assuming you're referring to dA: because it is lower or higher than the point of origin.

I think the confusion stems from an incomplete understanding of reference systems on an aircraft.
The forces and moments are arranged according to the right hand system.
A way to determine what direction the moments point is to use the your right and make a fist. Then point out your thumb. As in the image below:

Source
If you put your thumb on the positive direction (so let's say +X force), your fingers curl in the direction of the positive moment (thus in the direction of the arrow that says 'L').
Similarly for your question, we are talking about pitching moments (rotation around the Y-axis), so we have to point are thumb in the positive Y direction. Our fingers then curl with the clock (as seen from the Y-axis).
The N force is in the opposite direction, making for the - sign.

Source

You are right, technically the equation should have only plus signs, and the value of X would be negative. Also, the value of Y for the lower side forces should be negative while it is positive for the upper side forces. The author selected to subtract the lift force terms while he added both drag force terms even when one of them has a negative lever arm. This is sloppy.
The reference point of the moment is the leading edge, so all lift forces N act at a point behind this reference point. Positive is up and to the right, so a positive moment is trailing edge down. A positive lift force behind the reference point produces a negative moment, so to achieve a positive number the lever arm has to be negative.
In mathematical terms: Positive x is backwards, but you need to go forward in X to move from the force to the reference point. Hence a negative x. But there should not be a minus sign for the variable in the equation.

So the main reason for the negative sign is due the different direction for a "positive force" and a "positive moment" right?

@HarryYang: Positive X is backwards, but you need to go forward in x to get from the force to the reference point. Hence a negative x.

sorry for so many questions from a high school kid... That makes sense, but what about in y direction, the axial forces A for the upper surface, positive Y is upwards, but to get to the reference point you need to go downwards, in this logic, shouldn't the moment arm of y be negative as well?

@HarryYang: You are right, technically the equation should have only plus signs, and the value of X would be negative. Also, the value of Y for the lower side forces should be negative while it is positive for the upper side forces. The author selected to subtract the lift force terms while he added both drag force terms even when one of them has a negative lever arm. This is sloppy.

@HarryYang No need to worry about being a high school kid with many questions. I'd have been quite happy to have had my sons be so interested in things aeronautical.

why would the value of x be negative?

I'm not an aviation engineer, but a physicist, and see it like this:
There is a pressure $p$ acting perpendicular onto the airfoil, and $\tau$, which seems to be drag, acting parallel to the airfoil to the trailing edge.
Right?
If this is so, one can express the horizontal force $dA$ and vertical force $dN$ on the upper side as:
$$\begin{eqnarray}
p_x&=&-p\sin\theta\\
p_y&=&-p\cos\theta\\
\tau_x&=&\tau\cos\theta\\
\tau_y&=&-\tau\sin\theta\\
\hline
dN&=&p_y+\tau_y=-p\sin\theta-\tau\sin\theta\\
dA&=&p_x+\tau_x=-p\cos\theta+\tau\cos\theta
\end{eqnarray}
$$

Note: The direction of $dN$ is upwards, and that of $dA$ is to the right. The value of this expressions can be negative, making them effectively pointing into the other direction. But we don't have to care about this, math does for us.
Now, in physics, a momentum trying to rotate something counter-clockwise is positive, and a momentum trying to rotate clockwise is negative. But it seems in aviation a moment trying to lift the nose is positive, which in this case means that clockwise rotation is positive. Then, one gets:
An upwards pointing $dN$ tries to turn the wing counter-clockwise, and must give a negative momentum, i.e. $\int -x\cdot dN$. And $dA$ tries to turn the wing clockwise, and gives a positive momentum $\int +y\cdot dA$.
(Please excuse that I'm a bit sloppy about that infinitesimal stuff)

Now, in physics, a momentum trying to rotate something counter-clockwise is positive Does that depend on which side the pilot stands when he looks at the aircraft? Makes my head spin.

@Koyovis: Yes, this is called 'parity'. If you are standing left of an aircraft, a clockwise rotation means "nose up". If vou are standing right of an aircraft, "nose up" is counter-clockwise. Sounds weird, but if you think about, it is logical.

Not for the pilot who sits in the middle.

@Koyovis: think about the passenger sitting between the wings ;-). However, the rule still applies. Look out of the right and the left window when the AC rotates - how does the horizon move?

@sweber: I read your answer for several times but I could not see why you say dN is pointing upwards, isn't it in the diagram pointing downward?

@HarryYang: That's exactly the reason for this question. A vector (0;1) points upwards and would try to rotate ccw. Thus, we have to multiply with -x. But our vector is dN*(0, 1), and because dN<0, it finally points downwards. Another way to see it: The force acts downwards with an absolute value of |dN|, and could then just be multiplied with +x to get the correct result. MAybe, I'll expand my answer tomorrow.


text:
FL(Flight Level) vs Altitude
in my radio book i came across this communications.
Control: "Pacific 800 report passing FL 150"
Aircraft: "Pacific 800 Wilco"...
           "Pacific 800 passing FL150".
next.
Control: "Fiji 58 maintain 2500 feet"
Aircraft: "Maintaining 2500 feet Fiji 58"
What is the formal explanation for FL and altitude, cause i am confused both are the same thing.

Flight level is the indicated altitude when the altimeter is set to 29.92.  This is done above 18,000 feet.

@Riccati  In the U.S. it is done above 18,000'.  Other places have a different transition altitude, and in these places it can be entirely normal to have FL150 or FL080 or etc.

This depends on where you are in the world but under the FAA here in the US the FAA defines it as

Flight level means a level of constant atmospheric pressure related to
  a reference datum of 29.92 inches of mercury. Each is stated in three
  digits that represent hundreds of feet. For example, flight level 250
  represents a barometric altimeter indication of 25,000 feet; flight
  level 255, an indication of 25,500 feet.

In other words its the altitude if you set your altimeter to 29.92. In the US all aircraft in class A airspace (18,000 and up generally) set their altimeter to 29.92 thus flight levels are used at that altitude. When an aircraft is below Fl 180 the local altimeter setting is used.

"FL180" isn't quite the same as 18,000' -- with a high altimeter setting, FL180 can be much more than 500' above 17,500' MSL.  And with an altimeter setting below 29.92, FL180 won't exist (in the US) as a usable flight level.  I recognize that these distinctions probably boarder on pedantic, but it's good to distinguish how "17,000' MSL" is 17,000 feet above mean sea level, while "FL180" is 18,000' above a reference datum plane that usually is different from mean sea level.  (When the local altimeter setting is 29.92, then the two planes match up, but not otherwise.)

Remember all altitudes are not created equal.

Pressure altitude is altitude above a set reference datum
Density altitude is pressure altitude corrected for nonstandard temperature.
Absolute Altitude is the actual altitude above the ground at your present location above the planet
Indicated Altitude is your altitude above Mean Sea Level (MSL) corrected for pressure variations at that location.

Flight levels are a pressure altitude reading, that is a height above a standard datum (MSL at an ambient pressure of 29.92" Hg.).  This is used for a standard height reference at high altitudes (>18,000 ft MSL) so crews operating there can make use of a universal reference datum.  An airplane cruising at FL390 may or may not actually be 39,000 ft above MSL depending on ambient conditions but maintains a standard height from a universal datum for traffic separation in this airspace.
Lower altitudes will make use of indicated altimeter readings to indicate height above MSL.  This is favored because of the aircraft's proximity to terrain, providing appropriate reading for obstacle clearance, etc.


text:
Numerous questions regarding ARINC429 protocol
I recently made significant progress in my understanding on the ARINC429 thanks to a user on this site, but I after reading more into it, I may have confused myself a little bit. Any help on any of the following questions is greatly appreciated.

I found a specification pdf online, but it contradicts (i think) some of the other information I have gotten. The link to the pdf is here. Is it safe to assume that information is accurate enough to rely on? Assuming this book is a proper document on the ARINC429 specification
If the above is correct, is it correct that BNR data fields are represented in positive two's complement with bit 29 indicating its sign (positive/negative)? Wouldn't that just be regular binary with bit 29 indicating the values sign?
The scale factor applies starting from the MSB (bit 28) and continues halving with each bit between 27 and 11. The actual value translation would be applying the scale factor to each sig bit and adding the values of all the sig bits together to get the final value and using bit 29 to identify if its +/-. Is any of that correct at all?
How does the resolution work? I got confused a lot by that. What is it? How does it affect the data field?
Can somebody explain BNR format of the data field and how to translate it? I feel like I may have read too many different sources and got confused by the variance in explanations....haha

You should consider splitting this into multiple questions. You are asking five questions at once here.

Alright, I'll do that then, I just didn't want to annoy the other forum members with so many questions

On the first question, that is a link to A429 Part 1 supplement 17.  The current version is supplement 18. The differences are mostly some new labels for the MMR and Fuel controls.  Other than that it should be good for you.  BTW, Part 2 covers Discrete words and Part 3 Block data transfer (Williamsburg protocol).

Resolutions in the A429 spec are approximate, so calculate them yourself.
Resolution = Range / (2^significant bits)
Here is one way to do it:
Load your 32 bits into a signed 32-bit integer.
Shift left 3 so the sign bit is now in bit 32.
Shift right (32-significant bits)-1 to form a 2's complement "fixed-point" number.
Convert to float and multiply by the resolution.
Done.
Note that when a signed integer is used the high bit is sign extended on the shift right.
"Fixed-point" is also known as "scaled" in some circles. It's a method of storing and performing math on a real number using an integer rather than using a float. The resolution is the weight of one lsb bit. The resolution is documented somewhere and multiplied by the integer to get the float when debugging and such, but machine code does not "know" that you think of it as a float.
The range is key to fixed -point numbers because it bounds the value. The number of significant bits affects the accuracy. You could use the wrong number of significant bits and still get a "usable"  number but with a possible loss of accuracy if you choose one that is too small. Beware that unused low bits are sometimes repurposed for status flags, etc., so don't expect these to alway be zero. Also, the specs describes an ideal standard but in the real world liberties are taken with labels repurposed as needed.
Because of the way 2's complement integers work, the max positive value possible will be the range minus the resolution. For instance, you can get exactly -180 degrees but not quite +180 degrees.

Sorry, I think I may have gotten a little confused. When you say shift the bits left by 3 then right by -1 (basically saying shift left by 4), then convert that (I'm assuming it's still two's complement) into a float number, then multiply the float by the resolution, would that give me the translated version of the data field?

In A429 BNR there is a 2's complement integer (an ordinary integer) in the data field with the sign bit in bit 28. But this is not a 32-bit integer, its size is "sig bits" from the label's spec, plus one for the sign. You have to turn that into a 32-bit integer. The shift left will always be 3 to move bit 28 into but 32. This will anchor the sign bit (sign extend) so negative numbers stay negative. The you have to then shift the whole thing right so the LSB is in bit 1. The number of bits to shift right varies by the number of significant bits and must be calculated,.

Alright, so then once I have the sign bit anchored and I shift the sig bit right until the lsb of the datafield is bit 1. Would I pad the area between the sign bit and the msb of the data field with 0's? If so, would I just translate it to base10 or do I need to apply the scale factor from the msb to lsb as they talk about in the specification doc?


text:
How to start to get in the field of aviation with degree of Computer Science?
I am a 3-year computer science student and really want to go into the field of aviation, but not able to figure out what should I do at this point of time so as to have a career in this field.

You could work for an avionics company pretty much everything is going the way of the computer in the cockpit. Some heavy hitters are Garmin, Rockwell Collins or products like Foreflight

Are there any special courses that I need to opt? Dave

Avionics use all different languages but a solid understanding of micro-controllers/microprocessors can never hurt. A good understanding of how sensors (hardware) integrate into control systems would also be of use.

If at all possible, pursue a pilot licence.  In the US, it's almost free (whatever a CFI charges) to obtain a student pilot certificate, and the certificate does not expire.  When I was at this stage, I landed a technical job at a large aircraft manufacturer.  I was surprised how few of the employees were actually pilots.  It was a big advantage for me.

In my opinion having an aviation degree like aerospace engineering isn't a huge advantage, and for some roles they probably prefer someone with a strong software background. Most large avionics companies have separate control system design or aviation teams and a separate software team who handle lower-level architecture, compiling, building, testing, etc.  Evidence of your interest in and understanding of avionics could help though, including a course in aerodynamics, pilot training, or even things like
a control systems or embedded programming class.


text:
Can pilots land an aircraft with only the use of throttles?
Presuming that all other means of controlling an aircraft are unavailable to a pilot, can a pilot land a commercial airliner safely by using only the throttles and are pilots trained to do so?

Check out United Airlines Flight 232 on Wikipedia. https://en.wikipedia.org/wiki/United_Airlines_Flight_232

@JScarry Doesn't really meet the criteria of "safely" in the question ;)

Pilots are definitely not trained for that situation.

The realistic answer is no, and I very much doubt such training has ever been in any approved simulator training curriculum. Certainly I never received such training. It's probable, though, that people have played around with this when they've had simulator time to burn, but I've never heard of anybody succeeding. About the best that you could reasonably hope for would be to be able to choose where you're going to have the accident, which is basically what they did for the United flight mentioned by @JScarry. I doubt anybody could do much better than that United crew.

Related: What alternative methods are there for controlling a plane when flight control surfaces have failed? and NASA Manual Manipulation of Engine Throttles
for Emergency Flight Control and other Burcham / Fullerton papers.

I know a pilot who was towing a banner, and had the tow rope jam his elevator.  He was able to land safely using only throttle.  This is only a comment because it is not an airliner.

Not safely, no. According to the Wikipedia article on UA Flight 232, with only throttle control, it is impossible to "control airspeed independent from sink rate", because there's no control of angle of attack.
In 232's case, that meant:

On final descent, the aircraft was going 220 knots and sinking at 1,850 feet per minute, while a safe landing would require 140 knots and 300 feet per minute

I.e., even going 50% above safe landing speed the descent rate was 6 times too high. This is nowhere near safe, and it was something of a miracle that 185 out of the 296 souls aboard survived.
After that accident, the NTSB decided training for such a case wasn't practical.

1500 fpm is 15 knots for those of us curious about the sink rate vs airspeed trade off.

One successful landing using differential throttle alone has been made by an airliner (actually an A300 cargo variant). With hydraulics out due to a SAM missile hit, they brought the plane down to a safe landing with no further damage, using differential throttle alone.
DHL Baghdad landing

Not quite "no further damage" - the engines were destroyed by ingesting sand and razor wire after the aircraft ran off the runway.


text:
How to identify the FAP in runway during Landing?
How to identify the FAP in runway during Landing ?

What do you mean by "identify"? on a plate or visually?

The final approach point is part of an instrument approach and thus can be identified using navaids as outlined in the approach procedure.


text:
Are warbirds allowed to use afterburners?
Suppose a civilian buys a military jet, for example an T-38. Would he be allowed to use afterburners?

Though not an expert, I can say yes they are. But from what I can understand the aircraft would burn a lot of fuel; on top of that there is the question on the use of afterburner and sound : since you cannot go past Mach 1 over land in the US and Europe, unless you are in a specific area or over sea, what would it be used for ? I guess people will have more thorough answer than that and links to proper regulation on that subject.

@PierreChevallier -- some aircraft require AB for T/O operations (either under certain load conditions, or all the time); it may also be necessary to provide maximum thrust when such is called for, even if airspeeds are not high.

No, no restrictions on using an afterburner. There are a few F104 Starfighters on the civil registration that must use the afterburner to take off.
However, most countries forbid supersonic flight by non military operated aircraft in their airspace. The only time Concorde went supersonic was over the ocean.

Afterburners are pretty noisy by themselves, aren't they?

@Koyovis not all that much more than the same engine at full military power, and they tend to be used only for a short period because of the high fuel consumption and increased wear on the aircraft. Very few aircraft were designed to fly on afterburners for prolonged periods, and as far as I know there are no SR-71s in civilian hands (except maybe one owned by NASA).

A friend has a demilitarized warbird.  The full propulsion system remains intact.  Sometimes, in full view of the FAA, at airshows, he will light the afterburner. I know of no regulation which prohibits augmented thrust from afterburners.

Clarification, I know of no federal regulation on afterburners.  I have heard that some airports have regulations against it, unless required for takeoff.  Apparently done for noise abatement.  This came from the friend with a warbird.  He did not mention the airports.


text:
Understanding “Your true airspeed will be the same, but your airspeed as opposed to the ground is much faster.” Bhutan Paro International Airport PBH
CNN's September 17, 2024 This airport landing is so challenging only 50 pilots are qualified to do it is about

...Bhutan’s Paro International Airport (PBH), widely considered one of the most technically difficult plane landings in the world. Maneuvering onto a short runway between two 18,000-foot peaks requires both technical knowledge and nerves of steel.

The article goes on, quoting "...Captain Chimi Dorji, who has been working at Bhutan’s national state-owned airline, Druk Air (aka Royal Bhutan Airlines), for 25 years."

“In Paro, you really need to have the local skills and local knowledge area competence. We call it area competence training or area training or route training from flying from anywhere into Paro,” he tells CNN Travel.
Bhutan, which is located between China and India, is more than 97% mountains. Its capital, Thimpu, is 7,710 feet (2,350 meters) above sea level. Paro is slightly lower, clocking in at 7,382 feet.
“At higher elevations, the air is thinner, so the aircraft essentially has to fly through the air faster,” explains Dorji, who in addition to flying planes now trains Druk Air’s pilots and cabin crew. “Your true airspeed will be the same, but your airspeed as opposed to the ground is much faster.”

I don't understand the last sentence - what's the difference between "true airspeed" and "airspeed as opposed to the ground", and why would the latter be "much faster"?

And instead of "airspeed as opposed to the ground" we usually say "ground speed."

Looks like a bad translation or transcription of what the Captain probably said. Something like  “Your indicated airspeed will be the same, but your speed over the the ground is much faster.”

Sounds like the Captain was trying to dumb-down a slightly tricky couple of concepts, in a language that is not his own, and did a pretty good job of it, if we isolate a couple of bits: "the aircraft ... has to fly through the air faster"  &  "your [air]speed as opposed to the ground is much faster."  So: stall-speed is higher; landing speed is higher > ground speed is higher on touch-down.

something occasionally noted is the simplification of an explanation for ease of understanding by the general public...

The statement as given does not make much sense. The use of the term "airspeed as opposed to the ground" already indicates that imprecise terminology is being used here. This is called ground speed and is (as the name suggests) not an airspeed.
In general, aircraft take off and land at a given calibrated airspeed (which depends on weight and flap configuration). The true airspeed corresponding to this given calibrated airspeed will increase with altitude because the air is less dense. I think this is what pilot meant to say. This true airspeed is also equal to ground speed if there is no wind.
According to the article, Paro airport is at 7,382 ft AMSL. For standard atmospheric conditions, this means an calibrated airspeed of 150 kt will correspond to a true airspeed of ~167 kt (see e.g. aerotoolbox.com), an increase of ~11%. Note however that kinetic energy scales with velocity squared and is therefore increased by ~24%, resulting in significantly longer takeoff and landing rolls.

Thanks! OK so for whatever reason (mistranslation, mistranscription, misquote, editor's intervention, etc.) "Your true airspeed will be the same" is not right, but as RalphJ suggests "“Your indicated airspeed will be the same" would fix the 1st half, and "your ground speed would be (about) the same." would fix the 2nd half? Have I got the basic idea correct?

Yes, I agree that the first one should say indicated or calibrated instead of true airspeed (we usually use calibrated airspeed on an airliner). The second one should be "ground speed is much faster" (not the same).

Without entering into the details about the differences between indicated airspeed, equivalent airspeed, true airspeed or calibrated airspeed (and for sure I'm forgetting some other airspeed), what the interviewed pilot wanted to say (possibly not with the right wording) is simply that, being lift proportional to the product $\rho V^2$, if you're landing at higher altitude (i.e. lower density $\rho$) then you have to compensate for it by increasing $V$. Being a mountainous place, gusts mitigation might also dictate a further increase in the landing speed. As simple as that.


text:
What is this knob on a Martin-Baker Mk.4 ejection seat?
I'm trying to find out what manual controls are on the Martin-Baker Mk.4 ejection seat and there's a black and yellow spherical knob by the pilot's right knee that has escaped my researches.  I know it isn't the inertia reel control or the manual override handle and the PEC is usually a green box off to the side.
Any ideas?

Pictures courtesy of Carlos Menendez San Juan

Can you label the ones you do know? I would have said the one you're asking about is the manual override.

@OrganicMarble  None of the items I mentioned are visible in that photo.  The 'manual override handle' I was refering to is to separate the pilot from the seat without firing the ejection system (https://ejectionsite.com/emb2gen.htm) .  I looked at the document that Party_Ark linked to, and it's called the 'manual separation handle' there.

It is clearly a manual gearstick to control a manual transmission; also indicates this is a left-hand-drive aircraft.   (humour)

It is the Emergency Oxygen Manual Operating Handle

The emergency oxygen system has a gaseous oxygen storage bottle fitted
to the back of the ejections seat which feeds its supply through an
emergency oxygen demand regulator to the rear of the seat portion of
the PEC [Personal Equipment Connector] and thence into the oxygen mask tube. Emergency oxygen is
selected manually by pulling the emergency oxygen knob, or
automatically on ejection as the seat rides up the rails. When the
pilot separates from the seat after ejection, the separation of the
man and seat portions of the PEC breaks the emergency oxygen supply
and allows air to be breathed at ambient pressure.

source - English Electric Lightning F Mk 36 & T Mk 5 Flight Manual

Excellent answer!  That document is perfect!


text:
Flight Design CTSW vs Cessna 162 (Light Sport Airplanes)
I am going to buy a light sport aircraft in next couple of months and trying to make a decision between Flight Design CTSW and Cessna 162.
I have some budget within 50K and want inexpensive plane.
Flight Design CTSW (not CTLS) pros and cons:
I like its design and I like Rotax 912, but I am afraid of maintenance cost of rotax, parts and mechanics availability.
Cessna 162 pros and cons:
Looks like a little bit cheaper to buy. I like parts availability and mechanics. I don't care about that it burns more fuel and heavier.
Does anyone have some experience with one of these planes or would recommend a different make and model? (LSA only in USA). Thanks.

Is there a reason not to go with a Cessna 150/152?

Sport Pilot License

Don't have any personal experience, but having been around GA since the mid 70s, and looking them over, the CSTW wins hands down.
To have any kind of utility a 2 seater must have more than a 500lb useful load and the CSTW is over 600lbs based on a 701lb empty, although airplanes you find used will always be heavier, probably around 725 to 750lbs empty.  Still that's a pretty impressive useful load. Even if you don't care too much about the useful load because you fly by yourself all the time, at some point you will.
Any Skycatcher you find is going to be 875 lbs empty or more, with more or less the same gross (just about any airplane you buy used is quite a lot heavier than the published factor number as they pick up a pound here and a pound there from this and that over time).
Carbon structure, so no metal.  Made in Europe.  And the 912 family has proven to be a very reliable engine line.
So between the two, the Flight Design.  I wouldn't touch a Skycatcher, which has had structural issues where Cessna had to go out modifying wings, and it kind of has that taint of failure to it due to Cessna just kind of abandoning the program even though they had a fat order book (Almost certainly because they discovered they were losing money on them even with production in China).  Which is why they're cheaper.
Bottom line though is you must go for a ride in each to make an informed decision.

Thanks for detailed answer. Never heard about structural issues on skycatcher. Any thoughts on jabiru j230 with jabiru engine?

I like the Jab but it has had its own issues and older versions had serious problems.  Google "Jabiru reliability".  I'm not a huge fan of geared engines, but the Rotax is so widely used that doesn't seem to be an issue. The other problem with Skycatcher is the production in China means quality control is a real unknown and the airplane is becoming a bit of an orphan https://www.aopa.org/community/flying-clubs/flying-club-newsletter/2017/november/19/aircraft-spotlight


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May someone please suggest EHA design procedures for AFS?
Are usual electro-hydraulic actuator designs for aileron control employable for aeroelastic flutter suppression? If not, where can I find design procedures for this specific case?


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How were pilots selected and trained before the introduction of simulators?
I wonder, how were the pilots selected and trained before simulators were introduced.
The simulators allowed to test the coordination and reaction time of candidates. And they allowed the students to learn to manipulate the planes before they actually flew. And to train the pilots to work in different situations.
So how was it before the simulators?

I've never personally been in a simulator for training purposes, and I'm a pilot...

@Ron Beyer: Me too.  The reason airline pilots train in a simulator is simply cost: it costs a lot to fly a commercial aircraft, and it likely gets real expensive if you write one off practicing emergency maneuvers :-)  Still, I would bet that most, if not all, airline pilots learned basic flying in a single-engine prop plane.

"The simulators allowed to test the coordination and reaction time of candidates." Does that actually happen? I'm a pilot and I've never even heard of that, let alone done it. And my flight training was within the last few years. Perhaps the military does that for fighter pilots or some such thing, but most pilots don't have their skills measured by anything other than their flight instructor and designated pilot examiner watching how they fly a real airplane.

I have been in simulators, Level D, full motion.  The only physiological testing (if you call it that) is to be spun in an altitude chamber, at 4.5 to 7G and then have the chamber explosively decompressed, to see what I could tolerate (ie how many Gs at 25000 ft pressure altitude. For the Level D simulators, the emphasis is on procedures, aeronautical decision making and judgement, rather than reaction times.

The RAF have reaction time tests, but they have to filter a lot of applicants for the tiny number of fast jet pilot jobs.

If we define "pilot" as a profession, a job at an airline or at the military, then simulators are definitely being used for selection of candidates, they're very useful for that.

Almost every pilot learns to fly in an actual aircraft, this is one of the reasons all trainers have dual controls.

My first day out, ever, was in an actual plane, behind real controls, in the sky. No sim-time prior to that. The instructor talked me though takeoff and maneuvers (keeping an eye on everything and operating the rudder). All he did was radio coms, navigation and the approach/landing.
As for whats common:
The vast majority of American WWII pilots are said to have learned to fly in the piper J-3 Cub

The Boeing PT-17 Steraman and AT-11 Kansan were also popular.
In GA where everyone else gets their start the Piper Cherokee and Cessna 150 or 172 rule supreme.
Of course these planes are slow, benign and fairly safe by aviation standards. But what if you have some super fast, one of a kind, high flying, awesome supersonic jet gadget. You surely cant afford to ruin such a plane but still need to train pilots. Well in that case you just build yourself a dual cockpit custom trainer....

Even the space shuttle had a real flying trainer designed to mimic its approach characteristics.
All that being said simulators can be a big help if used properly.

Question: Who sits in the instructor seat the very first time? :)

When the wrights invented powered flight there were no instructors and they subsequently became the first issuers of licenses as well as early defacto instructors. Since then various organizations form the civil aviation authority which eventually became the FAA and similar military outfits have overseen pilot training and education.

Re trainers having dual controls, the only planes I've seen that didn't have dual controls were single-seaters.

@pipe: That's what test pilots are for.

@jamesqf many of the early Beach Bonanza's had a "toss over" yoke as did planes like the Spartan Executive both which were dual seat single control.

@Dave: Interesting.  I've never flown in either, though.  I wonder about the logic behind that design - off the top of my head, it seems as though it'd be more complex and failure-prone than dual yokes.  (And what of rudder pedals?)

Surely by now the Space Shuttle trainer should be past tense?

@jamesqf my assumption would be there was a need to hand off pilot duties in flight by the added weight of dual controls cut into the useful load to much. Dual controls were added fairly early on in the production run. As for design, on most GA planes the controls just connect to a central column, in some its behind the panel in the early Bo's its actually visible. Some planes had dual pedals but only have brakes on the pilots side.

@Dave: I was thinking primarily of torque/bending moment on that central column.  With dual controls you have two shafts, so the forces would be more equal.  So single control shafts would have to be stronger (= heavier).  But that's just my gut reaction...


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Is a fly-by tower legal for civilians not during a show?
Suppose a civilian wants to fly-by tower in a small plane, like a Cessna 172, would it be legal for him to do it?
I assume here that if it is legal he still would need to ask permission from the ATC.
The region in place would be USA and the European Union.

This would almost undoubtedly be considered reckless by the pilot. "Buzzing" the tower is something that happens in the movies, in real life it would be met with a license revocation.

It happens, it's not legal, but I've seen it happen even at a large international airport with helicopters and jets. Albeit not as close as in movies (at the international airport)

No, that is not legal.

4.6 Except when necessary for take-off or landing, or except by permission from the appropriate authority, a VFR flight shall not be flown: [...] at a height less than 150 m (500 ft) above the ground or water.

(ICAO Annex 2)
So unless you are taking off or landing (which you are obviously not, if you are right next to the tower), you are not allowed to fly below 500 feet - and control towers are not 500 feet high.
(The quoted rule is for VFR flights, which I consider to be on topic since you are asking about "a small plane, like a Cessna 172". Similar rules exist for IFR flights, but those are even stricter)

Does the 4.6 rule is applied only in the vicinity of the airport, or basically everywhere?

@JohnMayne Basically everywhere, although the FAA has a more relaxed view in that FAR 91.119(d) states that I can fly an aircraft at any altitude over an "other than congested area" so long as that I'm not less than 500' to any person, vessel, vehicle, or structure and that I'm at an altitude if my powerplant fails, I can make a landing without undue hazard to persons or property on the surface. Basically I could fly at 20' over the salt flats as long as I'm 500' from anything.

@Ron Beyer: Not at all uncommon to do that out around  Black Rock or other salt flats.

I was once flying a Bonanza and was unable to confirm gear down due to a mechanical problem. I reported the problem to the tower and they gave me permission to do a banana pass by the tower. They were able to visually confirm that my gear was down. (The plane had just had an annual and the mechanics left the mechanical gear indicators disconnected!)

Well under normal circumstances the answer is no and a circus stunt like that would be likely to cost you your license, dependant upon how strongly the FAA ASD wanted to pursue it under §91.13 Careless and Reckless Operation.
While buzzing a tower is frowned upon, pilots will sometime make low approaches over a runway as a kind of go-around maneuver.  General etiquette suggests making the maneuver at or above 500 ft AGL, but I've seen plenty of pilots make much lower passes over a runway at untowered airports.
Now on special occasions e.g. motion picture filming, airshow, and aerobatic demonstration flights, waivers can be obtained to make low altitude fly-bys pursuant to the terms of §91.905.  Waivers contains a specific scope and limitations upon which maneuvers may be conducted and on what days and times.  Written proposals for said maneuvers must be submitted for approval in writing to the responsible FSDO.


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Why do some companies perform their freight flights only during the night?
I heard that for example FedEx among others performs the majority of their flights during the night, the same goes for TNT. Is the reason for that is that during the day all of the freight is being collected and then loaded for delivery in the evening? Or is there another reason?

I imagine it might be because you can load the plane extra?  possibly because it is cooler outside?

Note that passenger aicraft can transport freight

FedEx transports freight for the US Post Office during the day. Many of the US aircraft that arrive from MEM early in the morning will be reloaded with mail and head back to MEM for the USPS sort. They return in the afternoon with the sorted mail, then are loaded with FedEx freight for the overnight sort in MEM. The USPS operation is not nearly as large as the regular FedEx operation, but there are actually quite a few flights during the day.

As the previous answers have stated, their schedules are determined by what best suits their needs. However, those schedules can be complicated by contractual and curfew requirements.
A contractual example: Thousands of expatriate Brits live in the south of Spain. They want their morning London papers. We would depart Stansted (just north of London) as soon as possible. We were contractually committed to have the load to Barcelona by 07:00 local, with huge penalties if we failed (the papers were worthless by noon), and then on to Palma de Mallorca. Hopefully by now, they transmit the papers electronically and print them locally.
A curfew example: A cargo flight departing Hong Kong bound for Chitose, Japan (refuel there then on to Anchorage). The old Kai Tak airport at Hong Kong had a 23:00 local curfew; Chitose had a curfew until 06:00 local. The solution to that was to depart Hong Kong just before the curfew, land at Taipei and park for a couple of hours (I forget the exact time), and then continue to Chitose to arrive just after 06:00 local.
All Japan airports at the time had a curfew from 23:00 local to 06:00. You could go out to the south end of the airport just before 06:00 local, and set your watch by the first arrival of what was tens of aircraft, both passenger and cargo, whose departure time was determined by the need to arrive as soon as possible after the airport opened

Why would newspapers be worthless by noon? It's still the same day...

These cargo companies specialized in overnight delivery. Basically, they have their last pickups in cities in the afternoon/evening(depending on timezone/flight durations), and then load it onto the aircraft and then the aircraft fly to the hub(s), where it's sorted and then put on the next mode of transport(truck or plane), to get to their final destination. The cargo companies do fly during the day, but often it's either special flights, or their second day air cargo that they run(2 day service).

I would think that this is one of the most important factors.  Many businesses aren't open at night, so it may as well ship while they aren't doing anything else anyway.

Another thing to consider, besides the need to get cargo to its destination in the morning (which is often but not always the case), is cost.
Many busy airports charge different fees for parking as well as landing and handling charges depending on time of day. That's also why many holiday charters fly at such ungodly hours, requiring the passengers to report for checkin at 2AM and the like.
They don't do it because it's fun for their employees, they do it because it's the cheapest time for them to operate. It may not save that much, but a few Euros here and a few Euros there make up most of their profit margin.
And an additional bonus for cargo operators for arriving in the dead of night is that the road network their customers rely on to get the goods from the airport to its final destination tends to be less busy at night than during the day as well in many places.

The road congestion point applies to the air, too. Won't be slotted into a holding pattern waiting for O'Hare to clear out its backlog.

@ceejayoz which is implicit with flying at slow hours :)

Also the air route fees may be lower during night, or not?

@yo' I don't know about that, possibly, never seen price lists of Eurocontrol or similar organisations.

Short answer is "logistics."
Many flights occur at night, but not all of them. The aircraft have to be repositioned.
First, they don't "only" perform flights at night, but many of the flights occur at night because of the logistics of shipping.
Taking UPS and FedEx as an example, many if not most of their business customers ship items during business hours. This means that during the day, the packages are making there way from offices, factories, stores, homes, to sorting facilities. Those cutoff times for next day delivery are based on how quickly they can get the packages to the last flight to the shipper's main hub. UPS (at least when I used to work there) used a hubs and spokes system on a very tight schedule. Where KSDF is the main central hub (there are other sub-hubs). It takes time to get the millions of packages every day from the shipper to the correct flights. In order for the system to get Next Day packages to their final destination, the days packages must be at their destination in the early AM so that they can be sorted and shipped around from KSDF to all of their main facilities, where they are further sorted and put into delivery trucks. If the flight leaves too early, then customer service suffers because Next Day packages can only be accepted early in the morning, the later the flight leaves, the more NextDay packages from customers can be accepted during business hours, even so, Next Day delivery usually has a cut-off time that is earlier than 5pm depending on your geographic location.
You can think of the UPS hub and spokes system as going out in early morning, and coming back a few hours after business hours (i.e. night flights). There was some local sorting and distribution, but most of the packages find their way back to the main hub (i.e. KSDF), or sub-hubs, in order to be put into the hub and spokes distribution system. So if you're shipping a nextday package from Southern California to Florida on UPS, the package would be picked up today, then transported to Ontario Airport (in southern California) where it would be sorted and placed into an aircraft container, this would be done between 5pm and about 8PM, then the container would be loaded on the last flight into KSDF which would depart about 9PM and arrived in KSDF early the next morning (due to time zones), then the package would be sorted and put on the Morning flight from KSDF to Florida where it would have to be sorted and put on a truck for delivery that same day.
While, in KSDF the aircraft that arrived from KONT would be loaded with packages going to the west coast and sent back to KONT. Where the whole process begins again.
NOTE: This is a simplified version of what happens, because it is highly complex, but you can see that evening flights make sense logistically, because the packages that are shipped during business hours have to make their way to the aircraft that flies back to the main hub. Local packages can be sorted locally for local delivery. Interestingly, there are occasions where a package will travel thousands of miles across the country only to be delivered a few hundred miles from where it was shipped. It just depends on the logistic channels that are available to the shipper.
UPS trivia: UPS operates its aircraft as an airline.

It's interesting looking at websites that show current air traffic during the North American late night hours. Aside from a few red-eye transcon flights, nearly everything in the air is going to or from either MEM (FedEx) or SDF (UPS.)

I didn't realize that SDF was the main hub for UPS, however, I can attest to the number of UPS flights leaving there. I was hanging out at about 2am just north of the airport (for reasons, all legal) when they began their departure. There was an aircraft passing overhead roughly every 45-60 seconds, alternating off of 35L & 35R. You'd have thought it was an aircraft carrier launching air cover. Irrelevant to the answer, but fascinating to watch.

@freeman that is so cool that you got to see that. I worked at KONT, so I was at the farthest end of one of those spokes. Although, KONT (at the time at least) was the 2nd largest UPS air/ground facility in the country, second only to SDF, and it was the departure point for the last inbound flight to SDF of the night. Any nextday packages that missed that flight were sent to Line Flights, to be flown in belly of commercial airline flights heading to SDF.

I worked as a tug driver at the FedEx Memphis hub for a few years. Sort would go from roughly 11pm to 2:30am. After sort my job was to run missorted packages to their flights before they left. Starting at 2:48am there was a pushback time every six minutes until 4:00. I'm not sure exactly how many flights were on each time, but it was organized so that there weren't two flights trying to pushback into the same part of the ramp at the same time. I'd guess 7 or 8. There were about 75 launches per hour.

Now that I think about it, the sort area I ran missorts for was the KONT and KHWD flights. A decent percentage of the missorts were packages that ended up at the ONT slide that were bound for Ontario, Canada, and packages that ended up at the HWD slide (which was the ramp that serviced Hollywood) that were meant for the HWO station in Hollywood, Florida.

SDF arrivals for the main inbound are from 11p-~2a, and the departure push for the outbound usually goes from 330a-530a(though that has shifted later this past month or so) During the peak hour of the inbound we accept ~58 arrivals in an hour, and outbound usually tops 60 in an hour... and each is about 120 aircraft

The business model for FedEx and similar companies focuses on the overnight transport of freight.  So the bulk of the freight is moved after normal "business" hours.
However, there is freight which is transported by day, including same day delivery, second day delivery, etc.
But the bulk of the incoming freight reaches the local station after 4PM, as trucks return, drop boxes are emptied, etc.
Also, generally the planes have much more weight capacity than is needed for the freight. So the cooler evening air is not a big deal. It is significant that they get better ATC routing at night, however.
For anyone into algorithms, the optimization problems in loading and routing freight are significant.

FWIW, I consulted to ops at FedEx Memphis for a couple of years.  They and UPS will add flights as necessary, day or night, to meet the demand.  Regional flights tend to run early in the evening, and then again, in the morning from about 4 or 5 until 8am.  It is largely a matter of matching to the flow that the "stations" have where trucks are loaded for delivery and unloaded for pickups.

Customer demand
Their most important customers are companies who generally work 9-5.  They want to make the most of their workdays.  So they want the carrier to deliver packages to them as early as 9am so they have the bulk of the day to process the work therein -- but take packages from them as late as 5pm (quitting time) so they can use the full day to produce.
Carriers give them the latter, unless it is logistically impossible to do so, and get reasonably near the former, typically delivering packages between 9 and 11:30 am if that is requested.
At 5pm, delivery trucks are running around collecting packages to be shipped.  By the time they get to the regional distribution center at the airport, and the packages get inspected and go through their initial sort into containers and loaded onto planes, it's at least 8pm if not later.
They fly to the main distribution center (e.g. Memphis) where their packages enter the Big Sort.  By the time new containers are filled and loaded, it will be probably 1-4am before planes are ready to depart.  Their departure may be held further for higher priority aircraft to depart (they have farther to go) or so they arrive when the destination airport is open.
Any package which only paid for 2- or 3-day service may be "bumped" at any point if space is lacking.  For instnace you can certainly pay for 2-day service from NYC to LA, but that is physically impossible to do with ground transportation, so it must be air -- and air can do it in 1.
Airport congestion
A lot of airports are very congested -- think Heathrow, JFK, Mumbai, or SFO (if there's a cloud in the sky and therefore they have to close 28L).
For some reason, people don't like to fly at night.  They like to fly during the day.  The storm of passenger-flight activity tends to simmer down around 8 p.m.
These congested airports have limited runway capacity, and they tightly manage it by allocating, well, "slots"... but it's more complicated than that.  The upshot is there's a lot of operational and financial pressure on freight carriers to mostly avoid peak passenger times.
For similar reasons, they try to limit their operations at busy airports (SFO, Montréal) and favor auxiliary fields (Oakland, Mirabel).  While OAK is a busy 1-runway airport, it has an adjacent general-aviation field that is perfect for FedEx's smaller planes.

Cargo operators use passenger airports as well. Night flights for passengers aren't popular for a variety of reasons. Which means there are less flights for passengers landing and taking off during the night hours freeing up slots for cargo.
So it makes sense to avoid daytime rushhour for cargo that doesn't have a sleep cycle to mess up.

As stated very eloquently above, UPS, FedEx and TNT have a hub and spoke model and are takt'd process for sorting sending out, collecting sorting and distributing.
However, there are a few lesser known cargo operators that fly at night to take advantage of the cooler temperatures.  With cool ambient air, the engines can produce more thrust before having the engines exhaust gas temperature exceeding operational limits.  This is the case when the engines are getting close to needing an overhaul.
This means that the load master can plan with more weight and make for a more profitable flight.  You will see some operators in middle America waiting for the temperatures to cool off before requesting permission for takeoff...  Flowers and fish to Miami...

Welcome to [Aviation.SE]! "...and are takt'd process..." would you please explain "takt'd" - that's a new on one me.